OP0139 EFFICACY AND SAFETY OF ABBV-599 HIGH DOSE (ELSUBRUTINIB 60 MG AND UPADACITINIB 30 MG) AND UPADACITINIB MONOTHERAPY FOR THE TREATMENT OF SYSTEMIC LUPUS ERYTHEMATOSUS: A PHASE 2, DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL
Authors: J. T. Merrill, Y. Tanaka, D. D’cruz, K. Vila, D. Siri, X. Zeng, K. D’silva, L. Cheng, T. Sornasse, T. Doan, D. Kruzikas, A. Friedman
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> ABBV-599 is a novel combination of elsubrutinib (ELS; a selective BTK inhibitor) and upadacitinib (UPA; a JAK inhibitor) that targets non-overlapping signaling pathways associated with systemic lupus erythematosus (SLE). <h3>Objectives</h3> To report results from SLEek, a phase 2, randomized, placebo (PBO)-controlled, parallel-group, multicenter study evaluating efficacy and safety of ABBV-599 and UPA monotherapy in adults with moderately to severely active SLE (NCT03978520). <h3>Methods</h3> Patients (pts) were randomized 1:1:1:1:1 to once daily (QD) ABBV-599 high dose (HD; ELS 60 mg + UPA 30 mg), ABBV-599 low dose (LD; ELS 60 mg + UPA 15 mg), ELS 60 mg, UPA 30 mg, or PBO. The primary endpoint was the proportion of patients at W24 achieving SLE Responder Index-4 (SRI-4) and steroid dose ≤ 10 mg QD; additional efficacy and safety endpoints through W48 are also reported. The pre-specified 2-sided alpha level was 0.1. <h3>Results</h3> 341 patients were enrolled. After a planned interim analysis when 50% of pts reached W24, the ABBV-599LD and ELS 60 mg arms were discontinued for lack of efficacy (no safety concerns). Of 205 continuing pts (ABBV-599HD n = 68, UPA 30 mg n = 62, PBO n = 75), baseline characteristics were well balanced. The primary endpoint (proportion achieving SRI-4 and steroid dose ≤ 10 mg QD at W24 vs PBO) was met by ABBV-599HD and UPA 30 mg. Key secondary endpoints were also achieved at W48 in both groups (<b>Table 1</b>). Overall flares and time to first flare were substantially reduced in the ABBV-599HD and UPA 30 mg groups through W48 (<b>Figure 1</b>). Anti-double stranded DNA antibodies were significantly decreased with both treatments. TEAEs considered related to study drug were 42.6% ABBV-599HD, 32.3% UPA 30 mg, and 33.3% PBO. There were no malignancies or VTE. There were 3 non-fatal CV events (1 MI on PBO and 2 ruptured cerebral aneurysms [1 each on ABBV-599HD and UPA 30 mg]); all were assessed as unrelated to study drug by investigators. No new safety signals were observed beyond previously known data for UPA or ELS. <h3>Conclusion</h3> ABBV-599HD (ELS 60 mg + UPA 30 mg) and UPA 30 mg demonstrated significant improvements in SLE disease activity and flares with acceptable safety through 48 weeks. <h3>Acknowledgements</h3> AbbVie and the authors thank the patients who participated in the study and all study investigators for their contributions. Medical writing assistance, funded by AbbVie, was provided by Callie A S Corsa, PhD, of JB Ashtin. <h3>Disclosure of Interests</h3> Joan T Merrill Consultant of: AbbVie, Alexion, Alumis, Amgen, Astra Zeneca, Aurinia, Bristol Myers Squibb, EMD Serono, Genentech, Gilead, GlaxoSmithKline, Lilly, Merck, Pfizer, Provention, Remegen, Sanofi, UCB, and Zenas, Grant/research support from: Astra Zeneca, Bristol Myers Squibb, and GlaxoSmithKline, Yoshiya Tanaka Speakers bureau: AbbVie, Astra Zeneca, Boehringer Ingelheim, Bristol Myers Squibb, Chugai, Daiichi-Sankyo, Eisai, GlaxoSmithKline, Gilead, Lilly, Mitsubishi-Tanabe, and Pfizer, Grant/research support from: AbbVie, Asahi-Kasei, Boehringer Ingelheim, Chugai, Daiichi-Sankyo, Eisai, and Takeda., David d'cruz Consultant of: GlaxoSmithKline, Lilly, and UCB., Karina Vila Consultant of: AbbVie, Daniel Siri Grant/research support from: AbbVie, Boehringer Ingelheim, Bristol Myers Squibb, GlaxoSmithKline, Gilead, Hoffman Laroche, Jansen, Lilly, and Sanofi, Xiaofeng Zeng: None declared, Kristin D'Silva Shareholder of: AbbVie, Employee of: AbbVie, Ling Cheng Shareholder of: AbbVie, Employee of: AbbVie, Thierry Sornasse Shareholder of: AbbVie, Employee of: AbbVie, Thao Doan Shareholder of: AbbVie, Employee of: AbbVie, Denise Kruzikas Shareholder of: AbbVie, Employee of: AbbVie, Alan Friedman Shareholder of: AbbVie, Employee of: AbbVie.